Much has been discovered about the properties of visual short-term memory (VSTM), but few mechanisms have been proposed to explain limitations such as its low maximum capacity (Luck & Vogel, 1997). One mechanism suggested to account for this outcome is that of biased competition (Desimone & Duncan, 1995), with growing evidence suggesting that increasing competition in early visual areas may result in fewer stimulus items being successfully recalled (Shapiro & Miller, 2011). It has previously been shown that VSTM performance on a change detection task can be enhanced by reducing competition, through dividing the to-be-remembered items into two sequential displays (Ihssen, Linden & Shapiro, 2010). However, the episodic nature of the sequential displays may also have benefitted VSTM (see Bowman & Wyble, 2007). The present study provides further support for the biased competition account by manipulating competition whilst holding constant the number of episodes in which the stimuli were presented. Using a modified change-detection task the ratio of items between two displays was varied between n : n (the same number of items in each display) and n : n+/-3 (three more items in one display), for displays of both low (4-5 items) and high set size (7-8 items). We found significantly higher k-values for the near ratios (n : n and n : n+/-1) than the far (n : n+/-2 and n : n+/-3). There was no significant main effect of set size, nor interaction. These results provide compelling evidence that inter-stimulus competition plays a role in VSTM.